1. Technical Field
Embodiments of the present invention relate generally to wireless digital communication technology and, more specifically, to a system and method for route learning and auto-configuration.
2. Description of the Related Art
A conventional wireless mesh network includes a plurality of nodes, each incorporating a digital radio transceiver. A given node may transmit payload data to one or more other nodes via the digital radio transceiver. The node may originate the payload data or forward the payload data on behalf of a different node. Similarly, a given node may receive the payload data from a different node to be processed or forwarded by the node. The wireless mesh network may include an arbitrary number of nodes and may include certain access points, configured to bridge data communications within the mesh network to a related service system, such as a wire line or optical communications network.
The digital radio transceiver may implement specific modulation and spectral utilization techniques to satisfy a particular set of technical requirements. For example, multi-channel frequency hopping spread spectrum (FHSS) may be implemented to avoid potentially excessive interference among nodes that are attempting to transmit on a common radio frequency channel in an arbitrary window of time. FHSS involves transmitting data on one radio frequency channel for up to a specified maximum time duration and subsequently transmitting on a different radio frequency channel for up to another specified maximum time duration. FHSS systems typically follow a specific channel hop sequence, which both the transmitter and receiver need to follow to maintain a reliable communications channel. The transmitter reduces average radio frequency energy associated with a given channel by hopping to a different channel after a specified maximum time duration, thereby reducing a probability of interference among nodes attempting to transmit on the same channel.
FHSS systems conventionally require the transmitter and receiver pair to be synchronized, which is typically accomplished via a synchronization procedure conducted between the transmitter and receiver. Overhead associated with the synchronization procedure and related transmission latencies can substantially reduce overall transmission efficiency and network throughput.
In a network that is typically represented by a utility network, the distribution part of the network may include a plurality of nodes located at end-pint utility meters with a smaller number of nodes acting as relays, and one or more Gateways providing egress to these end-point nodes. The utility network may also consist of the infrastructure part (substations, feeder stations, transformer locations, generation facilities) that is populated with monitoring and control sensors. These devices may also be part of the utility network that may be directly connected to the utility server via WAN or connected to the utility server via Gateways in the wireless network. The routing algorithm may be structured in such a fashion that these infrastructure nodes, and any selected distribution end-point nodes can establish bi-directional connectivity with minimal latency and via the fastest path. In some embodiments, these infrastructure nodes and select end-point nodes can have multi-egress capability to increase network reliability.
In a conventional network, routing advertisements from a first node are inserted into a beacon packet so that the node's neighbors receive the packet. In such a network, extra transmit time is not needed as would be necessary if unicasting to each neighbor but as a node joins more networks, a beacon packet can become large and prone to being dropped. Also, the beacon packet can be more prone to overlapping with other transmissions. Furthermore, because the beacon packet has limited size, more time may be needed to send multiple routing advertisements than cannot fit within a single beacon packet. Also, because the beacon is not retried at the link-layer, it can be important that it has a high probability of being received on a first transmission. Increasing the probability of being received on a first transmission, however, places further undesirable constraints on the network.
As the foregoing illustrates, what is needed in the art is a more efficient technique for handling routing overhead in a network such as a wireless mesh network.